Washington (CNN) -- The NAACP has passed a resolution that condemns what it feels is rampant racism in the Tea Party movement. Members passed the measure on Tuesday at the organization's 101st annual convention in Kansas City, Missouri.

Tea Party activists have swiftly denounced the action as unfounded and unfair.

The resolution pits the nation's oldest civil rights organization, with its storied history of wins on behalf of racial justice, against a grassroots conservative movement that has won some recent political races and is flexing its muscle in Republican circles.

"We take no issue with the Tea Party. We believe in freedom of assembly and people raising their voices in a democracy," Ben Jealous, president and CEO of the National Association for the Advancement of Colored People, said in a statement.

"We take issue with the Tea Party's continued tolerance for bigotry and bigoted statements. The time has come for them to accept the responsibility that comes with influence and make clear there is no space for racism and anti-Semitism and other forms of bigotry in their movement," Jealous said.

Tea Party leaders reacted to the NAACP action with swift and angry derision.

"I am disinclined to take lectures on racial sensitivity from a group that insists on calling black people, 'Colored,' " Mark Williams, national spokesman of the Tea Party Express, told CNN. "The Tea Party [movement] is about the constitution of this country...[and] ensuring equality for each and every individual human being."

Former Alaska Gov. Sarah Palin, a Tea Party favorite, said the charge from the NAACP is "false, appalling, and is a regressive and diversionary tactic to change the subject at hand."

"To be unjustly accused of association with what Reagan so aptly called that 'legacy of evil' is a traumatizing experience, and one of which the honest, freedom-loving patriots of the Tea Party movement are truly undeserving," she wrote in a posting on her Facebook page Tuesday night.

Palin said the only purpose of such an accusation is to dissuade Americans from joining the Tea Party, a movement she said is "motivated by love of country and all that is good and honest about our proud and diverse nation."

But NAACP leaders feel there is ample evidence to prove Palin and others who deny there is racism in Tea Party are wrong. Hilary Shelton, director of the NAACP's Washington bureau and senior vice president for advocacy and policy, laid out what the group feels is the proof during an interview with CNN.

"After observing Tea Party activities throughout the country -- which culminated with the outrageous and racist behavior of Tea Party activists during the historic congressional vote to pass into law comprehensive health care legislation -- the NAACP began more closely investigating the Tea Party. Specifically as it was reported to us that Tea Party activists spat on [Congressman] John Lewis, a veteran civil rights activist and associate to Dr. Martin Luther King, and called Congressman Emanuel Cleaver the 'N-word' and called [Congressman] Barney Frank ... one of the first openly gay members of Congress, the 'F-word,' " Shelton said.

The NAACP also claims that Tea Party activists have engaged in racist behavior, for example, by waving signs that degrade African Americans and President Obama, in particular. Also, the NAACP says, a number of Tea Party members think that issues of importance to African Americans get too much attention.

"Rather than talking about the real issues of these incidents that have happened ... [activists] wind up blaming the messenger," Shelton said. "It seems like its denial ... that allows them to focus on themselves."

Many Tea Party leaders have publicly denounced elements of prejudice. During a May 6 interview on ABC's "The View," Amy Kremer, chairman of the Tea Party Express, pointedly looked into the camera and told any prejudiced followers, "This is not a racist movement. We don't want you here. Go away if that's what you're about. We're about the fiscal issues and about being American."

Williams, the Tea Party Express spokesman, said, "We've had these people show up on the fringes of our group ... because we attract TV cameras. What these people all universally learn, the racist groups included, is that they're not welcome."

Other Tea Party leaders also have publicly spoken out against racism in their movement.

While Shelton acknowledged the effort from "a few" leaders, she said the level of repudiation is not stopping displays of racism from many Tea Party followers.

"Not only are some elements of the Tea Party movement being resistant to that [message of repudiation], but we've seen some elements acting out, in some cases in a violently racist behavior. And that is what we want to see stop," Shelton said.

Shelton cited the movement's loose-knit patchwork of small, local groups that might not toe the line of Tea Party leaders.